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Paraneoplastic Syndromes

Distant effects of cancer mediated by hormones, autoantibodies, or cytokines

Written by: Saygı Hospital Health Guide Editorial Board
Last updated:

This content has been compiled by the Saygı Hospital Health Guide Editorial Board and is periodically reviewed by a specialist physician.

This content is for informational purposes only and does not constitute medical advice. You can book an appointment at our Onkoloji department. Book Appointment →

What is Paraneoplastic Syndromes?

Paraneoplastic syndromes are remote effects of malignancy mediated by tumor-secreted hormones or cytokines, by tumor-driven immune responses cross-reacting with normal tissues, or by metabolic effects of the tumor. They may precede the cancer diagnosis by months and are sometimes the only clinical clue.

Endocrine paraneoplastic syndromes include SIADH (most often small cell lung cancer), Cushing syndrome from ectopic ACTH (small cell, carcinoid, medullary thyroid), and humoral hypercalcemia of malignancy from PTHrP (squamous lung, head and neck, renal). Neurologic syndromes include Lambert-Eaton myasthenic syndrome, paraneoplastic cerebellar degeneration, and limbic encephalitis, and are usually mediated by onconeural antibodies (anti-Hu, anti-Yo, anti-Ma2, anti-NMDA, anti-CASPR2).

Treatment focuses on the underlying tumor; many syndromes improve with effective cancer therapy. Symptomatic treatment includes water restriction or vasopressin antagonists for SIADH, ketoconazole for ectopic Cushing, bisphosphonates and denosumab for hypercalcemia, and immunotherapy with steroids, IVIG, plasma exchange, or rituximab for autoimmune neurologic syndromes.

Symptoms

Hyponatremia with low serum osmolality (SIADH)
Hypercalcemia with bone pain and altered mental state
Cushingoid features developing rapidly
Subacute cerebellar ataxia, limbic encephalitis, neuropathy
Proximal muscle weakness improving with use (LEMS)
Skin findings such as dermatomyositis, acanthosis nigricans

Risk Factors

Small cell lung cancer (SIADH, LEMS, ectopic ACTH)
Squamous cell carcinoma (PTHrP-mediated hypercalcemia)
Thymoma (myasthenia gravis, pure red cell aplasia)
Ovarian, breast, lung cancer (paraneoplastic cerebellar)
Hodgkin lymphoma (paraneoplastic pruritus, eosinophilia)

When to See a Doctor?

If you experience any of the following symptoms, seek medical attention promptly:

  • Unexplained hyponatremia or hypercalcemia
  • Subacute neurologic decline without local cause
  • Rapidly progressive proximal weakness
  • Suspicious skin or systemic findings without explanation

Treatment Methods

01
Search for and treat the underlying cancer
02
Water restriction and tolvaptan for severe SIADH
03
Bisphosphonates or denosumab for hypercalcemia
04
Ketoconazole or metyrapone for ectopic Cushing syndrome
05
Steroids, IVIG, or rituximab for autoimmune neurologic syndromes
06
3,4-diaminopyridine for Lambert-Eaton myasthenic syndrome
07
Multidisciplinary care across oncology, neurology, endocrinology

Which Department to Visit?

You can visit our Onkoloji department for these complaints. Our specialist physicians will create the most suitable treatment plan for you.

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Health Disclaimer: The information on this page is prepared for general informational purposes only. It does not replace medical diagnosis and treatment. Please consult your physician for your complaints. Saygı Hospital does not accept responsibility for actions taken based on the information on this page.